Datasheet

LTC3425
3
3425f
PARAMETER CONDITIONS MIN TYP MAX UNITS
PMOS Turn-Off Current CCM < 0.4V –80 mA
PMOS Reverse Current Limit CCM > 1.4V 0.6 A
Max Duty Cycle ● 83 90 97 %
Min Duty Cycle ● 0%
Frequency Accuracy R
T
= 15k ● 0.8 1 1.2 MHz
SHDN Input High V
OUT
= 0V (Initial Start-Up) ● 1V
V
OUT
> 2.4V ● 0.65 V
SHDN Input Low ● 0.25 V
SHDN Input Current V
SHDN
= 5V or 0V 0.01 1 µA
V
SHDN
= 2V –0.50 µA
REFEN, CCM Input High ● 1.4 V
REFEN, CCM Input Low ● 0.4 V
REFEN, Input Current V
REFEN
= 5V 0.01 1 µA
SYNCIN Input High (Note 7) ● 2.5 V
SYNCIN Input Low (Note 7) ● 0.5 V
SYNCIN Input Current V
SYNCIN
= 5V 0.3 1 µA
CCM Input Current V
CCM
= 5V 2 4 µA
SYNC Input Pulse Width Range ● 0.1 µs
SYNC Out High 3V
SYNC Out Low 0.4 V
REFOUT REFEN > 1.4V, No Load ● 1.190 1.220 1.251 V
I
SOURCE
< 100µA, I
SINK
< 10µA ● 1.184 1.220 1.252 V
Error Amp Transconductance 50 µS
Error Amp Output High I
LIM
Resistor = 75k 2.2 V
Error Amp Output Low 0.15 V
PGOOD Threshold (Falling Edge) Referenced to Feedback Voltage ● –9.5 –11.4 –13.5 %
PGOOD Hysteresis Referenced to Feedback Voltage ● 1.5 2.5 4 %
PGOOD Low Voltage I
SINK
= 1mA (10mA Max) ● 0.12 0.25 V
PGOOD Leakage V
PGOOD
= 5.5V ● 0.01 1 µA
SS Current Source V
SS
= 1V 2.7 µA
Burst Threshold Voltage Falling Edge ● 0.84 0.94 1.04 V
Burst Threshold Hysteresis 120 mV
ELECTRICAL CHARACTERISTICS
The ● denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 1.2V, V
OUT
= 3.3V, R
T
= 15k, unless otherwise noted.
Note 1: Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2: Current is measured into the V
OUTS
pin since the supply current is
bootstrapped to the output. The current will reflect to the input supply by
V
OUT
/(V
IN
• Efficiency). The outputs are not switching.
Note 3: Once the output is started, the IC is not dependent on the V
IN
supply.
Note 4: Total with all four FETs in parallel.
Note 5: The LTC3425E is guaranteed to meet performance specifications
from 0°C to 70°C. Specifications over the –40°C to 85°C operating
temperature range are assured by design, characterization and correlation
with statistical process controls.
Note 6: This IC includes overtemperature protection that is intended to
protect the device during momentary overload conditions. Junction
temperature will exceed 125°C when overtemperature protection is active.
Continuous operation above the specified maximum operating junction
temperature may impair device reliability.
Note 7: The typical logic threshold for this input is: V
OUT
/2